If you want a nice, airy case, take a look at the Antec SLK3700. Dual 120mm fan mounts means a nice amount of air with minimal whine (a larger fan doesn't need to spin as fast as a smaller fan to push the same amount of air). The case is useful in other ways, and it's not too expensive. It includes a decent power supply, too.
You sure there's no fan mount near the front of your case?